Through use of microorganisms, a variety of useful substances have been produced on an industrial scale, including foods such as alcoholic beverages, miso, and shoyu (soy source); and other substances such as amino acids, organic acids, nucleic-acid-related substances, antibiotics, sugars, lipids, and proteins. Such substances are useful in a wide range of fields such as foods, pharmaceuticals, and daily-use articles such as detergents and cosmetics, as well as raw materials for chemical products.
In such industrial production of useful substances by the mediation of microorganisms, enhancement in productivity is an important issue. One approach which has been employed for enhancing productivity is breeding, through a genetic technique such as mutation, a bacterium which produces a substance of interest. In recent years, accompanied with the development of microbial genetics and biotechnology, more effective methods based on a recombinant technique or the like have been focused for producing useful substances.
A number of studies have been conducted on promoters which are required for the transcription of genes. Regarding Bacillus subtilis, a promoter domain of an alkaline cellulase gene derived from Bacillus sp. KSM-64 strain (FERM BP-2886) (see, for example, Non-Patent Document 1), a promoter domain present on the upstream side of an alkaline cellulase gene derived from Bacillus sp. KSM-S237 strain (FERM BP-7875) (see, for example, Patent Document 1 and Non-Patent Document 2), and other promoter domains are employed as promoter domains which actively transcript a gene encoding a heterologous protein or polypeptide.
However, in order to reduce production cost in industrial production, there is demand for a promoter or a microorganism which realizes higher productivity.
Generally, a promoter domain has various sites relating to regulation of transcription. These sites play a role in promoting or suppressing expression of a gene by the mediation of external signals. For example, when a culture medium for microorganisms contains large amounts of catabolites such as glucose, the microorganisms utilize mainly the catabolites as carbon sources, and the expression of an enzyme for degrading higher-molecule sugar is suppressed. This phenomenon is called “catabolite repression,” which has been observed in E. coil, Bacillus, etc. Catabolite repression in Bacillus subtilis is known to occur at the transcription level. The domain which is involved in catabolite repression in Bacillus is called “catabolite responsive element (cre).”
Non-Patent Document 3 discloses that catabolite repression may be increased or reduced by a point mutation in a catabolite repression operator domain in the Bacillus subtilis-derived α-amylase gene. Meanwhile, in a promoter in the Bacillus subtilis-derived endo-glucanase, there is a nucleotide sequence similar to that of the catabolite repression domain of α-amylase, which is called a “catabolite repression operator-like sequence” (Non-Patent Document 2). However, the actual role of the sequence has not been elucidated.    [Patent Document 1] JP-A-2000-210081    [Non-Patent Document 1] Sumitomo et al., Biosci. Biotech. Biochem., 59: 2172-2175, 1995    [Non-Patent Document 2] Hakamada et al., Biosci. Biotech. Biochem. 64: 2281-2289, 2000    [Non-Patent Document 3] Weickert & Chambliss, Proc. Natl. Acad. Sci. USA, 87: 6238-6242, 1990